I can't really compare anything to the Nexus 5 since everything that's leaked is merely speculation but, the big selling point for me is the camera. 13mp sounds a lot better than 8mp. It's hard to go on just the camera alone though, we had this little Samsung phone from T-Mobile years ago and it only had an 8mp camera. It took better photos than our big digital camera ever did. I'm not to worried about not having the latest software because I would probably root and install a modded "kit kat" rom down the road anyway. I used to complain about not having an sdcard slot too but, now all my stuff is synced via google and I don't really find myself needing all that space. I should also mention that I'm not with T-Mobile but, MetroPCS. Anyon... (continues)
I almost held out for the Nexus 5, but Best Buy was offering a promotion and I got the LG G2 for free. Both look like good phones. I'd say the real question is whether or not you want to be stuck in a 2 year contract.